全文获取类型
收费全文 | 9949篇 |
免费 | 803篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 140篇 |
儿科学 | 350篇 |
妇产科学 | 249篇 |
基础医学 | 1318篇 |
口腔科学 | 127篇 |
临床医学 | 1312篇 |
内科学 | 1728篇 |
皮肤病学 | 120篇 |
神经病学 | 926篇 |
特种医学 | 375篇 |
外科学 | 1232篇 |
综合类 | 120篇 |
一般理论 | 8篇 |
预防医学 | 1097篇 |
眼科学 | 204篇 |
药学 | 680篇 |
中国医学 | 7篇 |
肿瘤学 | 779篇 |
出版年
2023年 | 67篇 |
2022年 | 95篇 |
2021年 | 215篇 |
2020年 | 152篇 |
2019年 | 228篇 |
2018年 | 255篇 |
2017年 | 187篇 |
2016年 | 199篇 |
2015年 | 241篇 |
2014年 | 275篇 |
2013年 | 492篇 |
2012年 | 602篇 |
2011年 | 571篇 |
2010年 | 344篇 |
2009年 | 291篇 |
2008年 | 473篇 |
2007年 | 465篇 |
2006年 | 458篇 |
2005年 | 382篇 |
2004年 | 419篇 |
2003年 | 383篇 |
2002年 | 340篇 |
2001年 | 237篇 |
2000年 | 241篇 |
1999年 | 236篇 |
1998年 | 98篇 |
1997年 | 74篇 |
1996年 | 78篇 |
1995年 | 69篇 |
1994年 | 66篇 |
1993年 | 61篇 |
1992年 | 166篇 |
1991年 | 148篇 |
1990年 | 154篇 |
1989年 | 142篇 |
1988年 | 120篇 |
1987年 | 127篇 |
1986年 | 139篇 |
1985年 | 124篇 |
1984年 | 97篇 |
1983年 | 75篇 |
1982年 | 60篇 |
1981年 | 56篇 |
1979年 | 105篇 |
1978年 | 80篇 |
1977年 | 67篇 |
1976年 | 60篇 |
1974年 | 51篇 |
1973年 | 59篇 |
1972年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
ABSTRACT: INTRODUCTION: Manual hyperinflation (MH), a frequently applied maneuver in critically ill intubated and mechanically ventilated patients, is suggested to mimic a cough so that airway secretions are mobilized towards the larger airways where they can easily be removed. As such, MH could prevent plugging of the airways. METHOD: We performed a search in the databases of Medline, Embase and the Cochrane Library from January 1990 to April 2012. We systematically reviewed the literature on evidence for postulated benefits and risks of MH in critically ill intubated and mechanically ventilated patients. RESULTS: The search identified 50 articles, of which 19 were considered relevant. We included 13 interventional studies and 6 observational studies. The number of studies evaluating physiological effects of MH is limited. Trials differed too much to permit meta-analysis. It is uncertain whether MH was applied similarly in the retrieved studies. Finally, most studies are underpowered to show clinical benefit of MH. Use of MH is associated with short-term improvements in lung compliance, oxygenation and secretion clearance, without changes in outcomes. MH has been reported to be associated with short-term and probably clinically insignificant side-effects, including decreases in cardiac output, alterations of heart rates and increased central venous pressures. CONCLUSIONS: Studies have failed to show MH benefits critically ill intubated and mechanically ventilated patients. MH is infrequently associated with short-term side-effects. 相似文献
192.
193.
Introduction
Retrospective analyses of specific subgroups of patients from the database of the ACTION study have evaluated the effectiveness of a nifedipine gastrointestinal therapeutic system (GITS) on clinical outcomes. These subgroups included those patients receiving: 1) full “optimal” therapy at baseline; 2) full “optimal” therapy at baseline but excluding renin angiotensin system (RAS)-blocking drugs; 3) treatment with nifedipine GITS who were not treated with RAS blockers versus those treated with RAS blockers but not nifedipine GITS. 相似文献194.
195.
Beta‐2 transferrin is detectable for 14 days whether refrigerated or stored at room temperature
下载免费PDF全文
![点击此处可从《International forum of allergy & rhinology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Thomas M. Zervos MD Mohamed Macki MD Bernard Cook PhD Lonnie R. Schultz PhD Jack P. Rock MD John R. Craig MD 《International forum of allergy & rhinology》2018,8(9):1052-1055
Background
The effect of time and temperature on beta‐2 transferrin stability in cerebrospinal fluid (CSF) is not well established. After collecting nasal CSF for testing, beta‐2 transferrin has been found to be stable and detectable for 1 week, whether being refrigerated or stored at room temperature. The purpose of this study was to determine if beta‐2 transferrin remained detectable longer than 1 week and whether refrigeration improved its detectability.Methods
In patients undergoing therapeutic CSF diversion, 2‐mL CSF samples were collected from 18 patients. The samples were divided and stored either at room temperature, or at 4°C, and tested for beta‐2 transferrin at 7 and 14 days. CSF was collected from external ventricular drains (EVDs) (n = 15), lumbar drains (n = 2), and subdural drains (n = 1).Results
Of the 18 CSF samples originally testing positive for beta‐2 transferrin, none turned negative at 7 or 14 days, in both the refrigerated and room temperature groups (95% confidence interval [CI], 0% to 18.5%).Conclusion
Beta‐2 transferrin remained detectable for 14 days in all CSF samples, regardless of being stored at 4°C or room temperature.196.
Park DC Polk TA Park R Minear M Savage A Smith MR 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(35):13091-13095
The present study investigated whether neural structures become less functionally differentiated and specialized with age. We studied ventral visual cortex, an area of the brain that responds selectively to visual categories (faces, places, and words) in young adults, and that shows little atrophy with age. Functional MRI was used to estimate neural activity in this cortical area, while young and old adults viewed faces, houses, pseudowords, and chairs. The results demonstrated significantly less neural specialization for these stimulus categories in older adults across a range of analyses. 相似文献
197.
O'Keeffe M Grumont RJ Hochrein H Fuchsberger M Gugasyan R Vremec D Shortman K Gerondakis S 《Blood》2005,106(10):3457-3464
198.
199.
Daniel Quan Lucía Luna Wong Anita Shallal Raghav Madan Abel Hamdan Heaveen Ahdi Amir Daneshvar Manasi Mahajan Mohamed Nasereldin Meredith Van Harn Ijeoma Nnodim Opara Marcus Zervos 《Journal of general internal medicine》2021,36(5):1302
BackgroundThe impact of race and socioeconomic status on clinical outcomes has not been quantified in patients hospitalized with coronavirus disease 2019 (COVID-19).ObjectiveTo evaluate the association between patient sociodemographics and neighborhood disadvantage with frequencies of death, invasive mechanical ventilation (IMV), and intensive care unit (ICU) admission in patients hospitalized with COVID-19.DesignRetrospective cohort study.SettingFour hospitals in an integrated health system serving southeast Michigan.ParticipantsAdult patients admitted to the hospital with a COVID-19 diagnosis confirmed by polymerase chain reaction.Main MeasuresPatient sociodemographics, comorbidities, and clinical outcomes were collected. Neighborhood socioeconomic variables were obtained at the census tract level from the 2018 American Community Survey. Relationships between neighborhood median income and clinical outcomes were evaluated using multivariate logistic regression models, controlling for patient age, sex, race, Charlson Comorbidity Index, obesity, smoking status, and living environment.Key ResultsBlack patients lived in significantly poorer neighborhoods than White patients (median income: $34,758 (24,531–56,095) vs. $63,317 (49,850–85,776), p < 0.001) and were more likely to have Medicaid insurance (19.4% vs. 11.2%, p < 0.001). Patients from neighborhoods with lower median income were significantly more likely to require IMV (lowest quartile: 25.4%, highest quartile: 16.0%, p < 0.001) and ICU admission (35.2%, 19.9%, p < 0.001). After adjusting for age, sex, race, and comorbidities, higher neighborhood income ($10,000 increase) remained a significant negative predictor for IMV (OR: 0.95 (95% CI 0.91, 0.99), p = 0.02) and ICU admission (OR: 0.92 (95% CI 0.89, 0.96), p < 0.001).ConclusionsNeighborhood disadvantage, which is closely associated with race, is a predictor of poor clinical outcomes in COVID-19. Measures of neighborhood disadvantage should be used to inform policies that aim to reduce COVID-19 disparities in the Black community.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11606-020-06527-1.KEY WORDS: COVID-19, disparities, disadvantage, socioeconomic status, race 相似文献
200.